The present invention relates to a method of manufacturing golf club heads, more particularly to a method of coating golf club heads being capable of decreasing the variation of coat thickness and improving the appearance.
Usually, in order to improve the appearance of a golf club head and prevent its metallic part from getting rusty, the golf club head is provided on the surface with a thin coat, using a hand-held spray gun by hand. As the shape of a golf club head is small and not a simple and has a round part, it is difficult to make a coat with a uniform thickness and thus the spraying work requires skill. If the coat is too thin, the strength thereof decreases and the coat is liable exfoliate. Hitherto, therefore, in order to avoid this problem, a considerable quantity of paint is sprayed on the golf club head, to be precise, sprayed towards the head. As a result, most of the sprayed paint, about 75% of the whole of the discharge quantity is not used. On the other hand, in order to provide beautiful metallic luster on the surface of the golf club head, a paint containing metal powder is used. In order that the metal powder shines, it is necessary that the particles of the powder are platy and the particles are oriented in normal directions such that the thickness direction of the particle becomes almost parallel to the surface of the coat. However, in case of the above-mentioned coating method based on the hand-held spray gun, it is impossible to orient the metal powder as explained above, and the directions of the particles are random.
It is therefore, an object of the present invention to provide a method of manufacturing golf club heads in which the coat thickness is uniformed and it is possible to orient platy particles of metal powder to improve the appearance of the golf club head.
According to the present invention, a method of manufacturing golf club heads comprises a process of coating golf club heads with a paint by passing the golf club heads through a space in which the paint is sprayed by an electrostatic spray coating machine so that the paint which is sprayed is changed and attached to the golf club heads.